i have a truma heater and when you turn it on with electric, it just blows cold air on 1/2 and 1 KW setting on the 2KW it is fine.if i put the gas on for a minute and then use the 1/2 and 1 electric heater it is ok. can any one help.
DAvid, the problem is probably that you have not reset the wall thermostat to a temperature higher than the ambient temperature.
Turn the wall control back until you hear a click, then forward until it clicks again, then a bit more, then try the electric heating.
If the weather is anything like here right now, it will have to be at the very highest setting, and even then it may not work as the inside van temp is too high.